1. Field of the Invention
The present invention relates to a ball grid array (BGA) type semiconductor device and its manufacturing method. Particularly, it relates to the improvement of a repairing method of defective solder generated when the BGA type semiconductor device is mounted on a motherboard.
2. Description of the Related Art
Since BGA type semiconductor devices (packages) can have a larger number of external terminal pins as compared with quad flat packages (QFPs) and small outline packages (SOPs), such BGA type packages have recently been developed.
In a prior art method for manufacturing a BGA type semiconductor device, a semiconductor chip is mounted on a first surface of an interposer substrate. On the other hand, solder balls are provided on a second surface of the interposer substrate. As a result, the semiconductor chip is electrically connected via through holes having a relatively small diameter provided in the interposer substrate to the solder balls. Next, the BGA semiconductor device is mounted on a motherboard by soldering the solder balls thereto. This will be explained later in detail.
In the above-described method, an open state or a short-circuit state may be generated due to the defective soldering process. In order to repair the open state or the short-circuit state, the interposer substrate is separated and detached from the motherboard by a heating process using hot air blown via through holes provided within the motherboard (see JP-A-9-181404) or by a special local heating process using hot air blown via nozzles provided at the periphery of the BGA type semiconductor device (see JP-A-11-26929). Then, the surface of the motherboard is cleaned, and solder paste is again adhered thereto. Finally, a new BGA type semiconductor device is mounted on the motherboard. Note that BGA type semiconductor devices including such defective solder balls are usually discarded. Thus, the manufacturing cost is increased.
It is an object of the present invention to decrease the manufacturing cost of BGA type semiconductor devices.
According to the present invention, in a BGA type semiconductor device including an interposer substrate having first and second surfaces, a semiconductor chip mounted on the first surface of the interposer substrate, and solder balls formed on the second surface of the interposer substrate, a plurality of through holes are formed within the interposer substrate, and each of the solder balls clogs one of the through holes of the interposer substrate.